ok,,, is your car a 115 body style ?

By 1977 they show an injection pump with automatic altitude correction... maybe you could put one of those on ... (?)
It also says that "accurate regulation and adjustment of injection pump is possible on an injection pump test bench only".
I hate those kinds of pronouncements.... but they say if you have that kind of bench the necessary data is available...

Do you have the 615 or 616 engine ?